In the growing field of robotics and clean electricity generation, new methods of mechanical actuation will be valuable in developing different types of robotic and power generating systems. Before the advent of optical mice, a traditional mouse generated directional signals for the cursor on the screen via a rubber ball which was in contact with two roll pins mounted perpendicular to one another in the XY plane. This allowed the cursor on the computer screen to move in any direction with respect to the XY plane of the screen. When moving the mouse forward or backwards with respect to the user, only the y-roller pin would be actuated and the mouse on the screen would move up and down. When the mouse was moved from side to side, only the x-roller pin would move and the cursor would move side to side on the screen.
However when the mouse was moved at a diagonal with respect to the user, a combination output of the roller pins would allow the cursor to move at various vectors with respect to the XY plane of the computer screen. In this sense, the roller pins of the mouse were passive devices that took “input” from the trackball and then displayed that motion as movement of the cursor on the screen. Furthermore, if these pins were actuated via a motor and “outputted” motion to the trackball, a force feedback mouse could in theory be created. This is an excellent way to create motion in a robot, or in theory to even generate electricity, but is limited by the fact that the rubber on plastic interaction between the track ball, and the rolling pins is unable to generate large amounts of torque.
Furthermore, when the x-pin for example is actuated by the track ball, the rubber ball will actually “drag” along the y-roller pin and will generate friction. This is true in the opposite situation as well. When both pins are being actuated (when the mouse is moving for example at a 45 degree angle) there is drag occurring on both pins. Thus, in addition to the inability to create large amounts of torque this device also creates friction between the trackball and the roller pins. This is acceptable in some robotic systems such as those seen in U.S. Pat. No. 5,952,796 entitled “Cobots”, as well as in U.S. Pat. No. 5,923,139 entitled “Passive robotic constraint devices using non-holonomic transmission elements”, the entireties of which are herein incorporated by reference. However in systems that require larger amounts of torque with lower friction, the surface-to-surface trackball system cannot work in its purest form.
Accordingly, an improved system and method for generating high-torque and low-friction for two-degree of freedom mechanical applications is desirable.